/u/darkhearted_raven I know you're no longer working on RS3 (still sad/mad about that, by the way), but perhaps you can re-reconfirm this?
It's been so long since I've looked at that code now, but the way it was originally coded was that ravensworn was a byproduct of rolling the mysterious trait. Of course ravensworn also should read as mysteirous in terms of breeding, so naturally the two link together. So there IS some benefit of rolling ravensworn together, but it should be no easier than two mysterious parents.
Though it might also have been edited since my time.